Defect-Rich Heterogeneous MoS/rGO/NiS Nanocomposite for Efficient pH-Universal Hydrogen Evolution.

Molybdenum disulfide (MoS) has been universally demonstrated to be an effective electrocatalytic catalyst for hydrogen evolution reaction (HER). However, the low conductivity, few active sites and poor stability of MoS-based electrocatalysts hinder its hydrogen evolution performance in a wide pH range. The introduction of other metal phases and carbon materials can create rich interfaces and defects to enhance the activity and stability of the catalyst. Herein, a new defect-rich heterogeneous ternary nanocomposite consisted of MoS, NiS and reduced graphene oxide (rGO) are synthesized using ultrathin αNi(OH) nanowires as the nickel source. The MoS/rGO/NiS-5 of optimal formulation in 0.5 M HSO, 1.0 M KOH and 1.0 M PBS only requires 152, 169 and 209 mV of overpotential to achieve a current density of 10 mA cm (denoted as η), respectively. The excellent HER performance of the MoS/rGO/NiS-5 electrocatalyst can be ascribed to the synergistic effect of abundant heterogeneous interfaces in MoS/rGO/NiS, expanded interlayer spacings, and the addition of high conductivity graphene oxide. The method reported here can provide a new idea for catalyst with Ni-Mo heterojunction, pH-universal and inexpensive hydrogen evolution reaction electrocatalyst.